Apparatus for injecting bulk solids into material contained in a vessel



Allg- 10, 1965 E. E. MUELLER ETAL 3,199,924

APPARATUS FOR INJECTING BULK SOLIDS INTO MATERIAL CONTAINED IN A VESSEL Filed April 18, 1963 3 Sheets-Sheet 1 JNVENTORKS EDWA RD EMUELLEP DONALD B.BAR1-z MELV/N J CHR/.sTE/VsE/v MA/fv//v C." Mc/ELLER TT'ONE V5 u8 l0 1955 E. E. MUELLER ETAL 3,199,924

APPARATUS FOR INJECTING BULK SOLIDS INTO MATERIAL CONTAINED IN A VESSEL Filed April 18, 1963 3 Sheets-Sheet 2l I/vvE/v 'roms .EDWARD EY Mae-LER 17m/ALU B. BAAN-z MELv//v J HR/s rE/VJEN MA///N C'. MUELLER ATTORNEYS Allg 10, 1965 E E. MUELLER 5ML., 3,99,924

APPARATUS OR INJECTING BULK SOLIDS INTO MATERIAL CONTAINED IN A VESSEL Filed April 18, 1963 5 Sheets-Sheet 3 IN VEN TOPS EDWARD .E MUELL Efe DONALD B. BARTz MEL V//v .I CHR/5 TENJEN MAV/N C. MUELLE/e AT Tom/Em United States Patent O :W95-,924 APPARATUS FR INliEtCTlNG BULK SLEDS ENT@ MATERHAL CNEALNED EN A VESSEL Edward E. Mueiler, Excelsior, Donald B. liartz, St. Paul, Melvin .l1 Christensen, Fridiey, and Marvin C. Mueller, .Le Sueur, Minn., assignors to Whirl-Air-Flow Corporation, Minneapolis, Minn., a corporation of illinois Filed Apr. 18, H963, Ser. No. 273,9?i 3 Ciairns. (Cl. Sill-446) Gur invention relates generally to injection apparatus, and more particularly to apparatus for injecting bulk solids into containers wherein the material in which said solids are to be injected is under pressure greater than atmospheric pressure, such as in foundry cupolas, mixing chambers and the like.

More specifically, our invention relates to improvements in apparatus of the `type disclosed in United States Letters Patent to Alfred Rexroth, No. 2,784,037, issued March 5, 1957, and has for one of its important objects the provision of an injector tube adapted to direct bulk solids into the material in a vessel and of novel means for preventing said material from coming into contact with said injector tube.

Another object of our invention is the provision of means for injecting said builk solids into the material in predetermined amounts.

Another object of our invention is the provision of means for injecting charges of the bulk solids into said material at predetermined time intervals.

To the above ends, we provide a solids metering or measuring apparatus, a first hopper for reception of said solids form the metering apparatus, a second hopper for reception of a predetermined charge of said solids from said rst hopper, a charging chamber for reception of said solids charged from the second hopper, valves for controlling flow of said bulk solids from the first to the second hopper and from the second hopper to said charging chamber, means for injecting said bulk solids from the charging chamber into the vessel through the injector tube, and means for maintaining a predetermined minimum pressure in the charging chamber and injector tube at least as great as the pressure of the material in said vessel.

Still another object of our invention is the provision of a charging chamber having a tapered portion shaped to permit easy discharge of the bulk solids therefrom and to prevent said solids from lodging in the chamber when ejecting force is applied therto.

Yet another object of our invention is the provision of novel means `for aerating the bulkvsolids during injection thereof to prevent undue compaction thereof during its travel from the charging chamber toward said chamber.

Another object of our invention is the provision of novel control means whereby the above apparatus may be operated in definitely timed cycles or wherein the timing or portions of said cycles may be manually controlled, as desired.

Another object of our invention is the provision of injection apparatus as set forth, which is relatively simple and inexpensive to produce, which is highly efficient in operation, and which is rugged in construction and durable m use.

The above, and still further highly important objects and advantages of our invention will become apparent from the following detailed specification, appended claims and attached drawings.

Referring to the drawings,- which illustrate the invention, and in which like reference characters indicate like parts throughout the several views:

FlG. l is a fragmentary view partly in side elevation Patented flug. l, 1965 ICC and partly diagrammatic, some parts being broken away and some parts being shown in section;

FIG. 2 is a view corresponding to a portion of FIG. 1, with some parts broken away and some parts shown in section;

FIG, 3 is a diagram showing the fluid pressure valve operating mechanism of our invention; and

FiG. 4 is a wiring diagram.

Referring with greater detail to the drawings, numeral 1 indicates a conventional foundry cupola which comprises an outer metallic shell 2 and a lining 3 of refractory material. Such cupolas are well known in the art, and, in the interest of brevity, further detailed showing and description thereof is omitted. The numeral 4 indicates molten material, such as iron or steel, in the cupola 1.

The preferred embodiment of our invention illustrated is primarily intended for use in injecting predetermined charges of bulk solids directly into the molten metal 4 within the cupola l for the purpose of producing an alloy of said metal, the bulk solids usually being in the nature of granular or powdered alloying material. Heretofore, and as disclosed in the above-identified patent to Rexroth, such bulk solids are introduced to the cupola in what is described as the melting zone of the cupola, which Zone lies above the normal level of the molten material within the cupola.

The apparatus of our invention involves a generally vertically disposed conduit 5 which extends downwardly from a suitable receiving hopper, not shown, for delivering the bulk solids to a feeding device 6 that delivers the bulk solids to a first receiving hopper 7, from whence the solids are delivered to a second receiving hopper 8. A housing 9, comprising a pair of cooperating housing sections 16 and iti, bolted or otherwise rigidly secured together, as indicated at 12, define a charging chamber i3 underlying the second receiving hopper 8 and adapted to receive the bulli solids therefrom. The housing section 11 is rigidly secured to the cupola l by means of a flanged tubular adapter element ld in which is mounted an injector tube l5 of high heat resistant material, such as stainless steel, graphite or the like. rihe injector tube l5, as well as the housing 9 and adapter element 14, slopes downwardly toward the cupola l, the discharge end of the injector tube l5 being contained in a counterbored portion 16 of a downwardly and inwardly sloping opening 17 in the refractory lining 3 of the cupola 1.

The feeding device 6 comprises a casing i8 which defines a cylindrical chamber 19 having an inlet 2u cornmunicating with the conduit f3 and an outlet 21 that cornrnunicates with the first receiving hopper 7. A multibladed Aor vaned rotor 22 is suitably journalled in the casing i8 and is rotated by a speed reducer equipped motor 23 in a manner hereinafter to be described. The bottom of the hopper 7 is provided with an opening 24 for passage of bulk solids to the hopper 8, the opening 24 being defined by a valve seat element 25 that is adapted to be engaged by a valve element 26 at the lower end of a piston plunger rod 27 which extends upwardly through the hopper 7 and axially inwardly of acooperating fiuid pressure cylinder 23 suitably mounted on the hopper 7. In like manner, the second receiving hopper 8 is provided at its bottom portion with a delivery opening 29 communicating with the charging chamber 13 and in which is mounted a valve seat element 3@ that is adapted to seat a valve element 3l at the lower end of a piston plunger rod 32 that extends upwardly though the hopper 8 and axially through a cooperating liuid pressure cylinder 33 mounted fast on the hopper 8.

Operation of the valves 26 and 31 is controlled by a valve 34 comprising a valve body 35 and a valve element or spool 36 that is movaole in one direction within the Valve body 35 by a solenoid 37 and yieldingly urged in the opposite direction by a spring 3S. The valve body 35 is provided with an inlet 39 for fluid, such as air, under pressure, a pair of exhaust outlet ports 4i) and 41, and a pair of cylinder ports 42 and 43 the former of which is connected to the upper end of the cylinder 28 by'a conduit 44 and the lower end of the cylinder 33 by a portion of the conduit 44 and a branch conduit 45. The cylinder port 43 communicates with the upper end of the cylinder l 33 by means of a conduit 46 and with the lower end of the cylinder 28 by a portion of the conduit 46 and a branch conduit 47. A pair of one-Way restrictor devices 48 and 49 are interposed in the conduits 44 'and 46 respectively intermediate the upper ends of their respective cylinders 23 and 33 and their respective branch conduits 45 and 47. Each of the devices 45 and 49 includes a housing 50 defining a valve seat 51 and having a valve member 52 that is yieldingly urged toward seating engagement With the seat 51 by a spring or the like 53. The valve member 52 is provided with a central metering aperture 54 which restricts ow of air under pressure to the upper end of its` respective cylinder 28 or 33 when the valve member 52 is seated on its respective valve seat 51, whereby to cause its respective valve element 26 or 31 to open at relatively low speed. With reference to FIG. 3, it will be seen that, with the valve element 36 disposed as shown, air under pressure is directed to the restrictor device 4S to the upper end of the cylinder 2S to slowly move the valve 26 to its open position. At the same time, airis conducted through the conduit 45 to the lower end of the cylinder 33 to move the valve 31 toward a closed position. VAir from the upper Vend of the cylinder 33 tlows through the conduit 46 to unseat the valve member 52 of the Vrestrictor device 49, whereby air Hows rapidly through the conduits 45 and 46 to rapidly move the valve element 31 to a closed position. When the solenoid 37 is energized to move the valve spool 36 to the right with respect to FIG; 3, the valve element 26 will rapidly move to a closed position, while the valve element 31 will lslowly move toward its open position.

As shown in FIG. l, the opening 29 to the charging chamber 13 is disposed intermediate the ends of the chamber 13, the portion of said charging chamber adjacent the opening 29`being of relatively large crosssectional area. The portion of the chamber 13 dened by the housing section 11 tapers gradually to provide a relatively small outlet 55 `through which the bulk solids are introduced to the injector ,tube 15. At the opposite end of the housing 9, gas, such as air, is adapted to be introduced to the charging chamber 13 at relatively high pressure from a suitable source, not shown, through a pipe 56, a valve 57, and a pipe fitting 58 connected to the adjacent end .of the housing section 19. The valve 57 is normally closed, and is adapted to be opened by a solenoid 59. A check valve member 6@ is vpivotally mounted in the housing section 11 and is yieldingly urged toward its normally closed position illustrated, by gravity or suitable spring means, not shown. When a charge of bulk solids is introduced to the chamber 13 from the second hopper S, the check valve 6@ prevents flow of the bulk solids to the outlet 55 until the valve 57 is opened. The pressure of air introduced to the chamber 13 through the pipe 56 is preferably in the neighborhood of 80 pounds n per square inch or more, such pressure being suiicient to cause opening of the valve member 66 and injection of the bulk solids from the chamber 13 and into the molten metal 4 in the cupola 1. A relatively small diameter aerating pipe 61 is connected at one end to the tting 5S, and at its other end to the housing section 11 between the check valve member 6i) and outlet 55, whereby to aerate the bulk solids during movement toward the injector tube 15 whenrthe high pressure valve 57 is open, whereby to prevent undue compaction of the bulk vmaterial as it is forced through the tapering Vportion of the' chamber 13 and into the injector tube 15.

The operation of the above-described apparatus is as follows:

Assuming that the conduit 5 contains an adequate supply of granular or powdered alloying material, the feeding rotor 22 is caused to rotate to deliver a predetermined quantity of bulk solids to the first receiving hopper 7. The valve element 26 is slowly moved to its open position while the valve element 31 is quickly moved to its closed position, the material within kthe Vhopper 7 being discharged by gravity to the second hopper 8. The valve element 26 is then quickly moved to its closed position and the valve element 31 slowly moved-toits open position to cause gravity discharge of the material from the hopper 8 to the charging chamber 13. Meanwhile the feeding rotor 22 is again caused to rotate to deliver a second charge of bulk solids tothe irst receiving hopper 7. When the material from lthe second hopper 8 has been delivered to the chamber 13, the valve elements 26 and 31 again moveto their closed and open positions respectively. With'the valve element 31 in its closed position, the valve 57 is opened to permit high pressure air to be introduced tothe chamber 13 from whence it propels the charge therein through the injector tube and into the molten metal 4 with such force thatV the bulk solids become dispersed in the molten metal and quickly melted and thoroughly mixed therewith. It will be noted, that as the .bulk solids are propelled through Vthe chamber portion defined by the housing section 11, the bulli particles tend to be compacted together and to be injected into the cupola 1in the form'of an elongated plug. Introduction of high pressure air to the outlet end portion of the chamber 13 through the pipe 61 prevents over compaction of the charge, so that the particles of bulk material are easily dispersed in the molten metal 4 by the blast of propelling air. The valve 57 is maintained in an open condition for only Vthe length of time necessary to propel the. charge intolthe cupola, after which the valve 57 is closed and the chamber 13 is again ready to receive a subsequent charge of bulk solids. y

f The injection of `bulk solids of the `above-described variety directly into the molten material has .at least one advantage over the practice of injecting the material into the melting zone above the molten metal. Not only does the charge of bulk solids become well dispersed gin the molten metal when injected directly thereinto, but oxidation thereof ,duringfthe melting thereof is reduced to a minimum or eliminated altogether. AV difliculty with this arrangement lies in the factthat the delivery end of the injector tube 16 is disposed below the level of the molten metal and is subjected to Contact therewith during periods when the valve 57 is closed and as the molten metal 4 tends to seek its own level in the opening 17 and injector tube 15. Thus, with each opening of the air valve 57 the molten metal in the opening 17 and injector tube 15 is forced inwardly into the cupola by the pressure of incoming propelling air, leaving a deposit lof metal on the interior of the injectorY tube 15. With each charge of bulk solids injected intovthe cupola 1, the metal deposit thickens in the injector-.tube 15 Vuntil the opening therethrough becomes so small as to prevent injection of the bulk solids. i

We have found, ,that byv maintaining a relatively low pressure within the chamber 13 and injectorl tube 15 at al1 times during operation of thejcupola, we are able to` prevent molten metal 4 from entering the opening 17 and coming into contact with the discharge end of the injector tube ,15. For the purpose of so pressurizing the the chamber 13 and injector tube`15, we provide anV air pipe 62 that is adapted to be coupled to the source of air pressure, not shown, and which is provided with a pressure regulator valve 63 and a check valve 64, the pipe 62 communicating with the chambe'r'13 intermediate the outlet'55'thereof and the check valve 60. Also interposed in the` pipe or conduit 62 is a supply valve 65 operated by a conventional solenoid 66. It will be noted that the check Valve 6) is suliciently loosely mounted in the chamber 13 to permit relatively free movement of air therepast from the pipe 62 to the porti-on of the chamber 13 underlying the valve element 31. The pressure regulator valve 63 is set to admit air to the chamber 13 at a pressure sutiicient to prevent llow of the molten metal 4 into the opening 17. This pressure might be approximately `from 2 to 15 pounds per square inch depending upon the depth of the molten metal 4. In order to maintain this pressure in the chamber 13 and injector tu-be 15 when the valve element 31 is opened, or when the valve 57 is closed, at which time there is a tendency for the molten metal in the cupola to surge into the opening 17, we provide a surge tank 67 which communicates with the air supply pipe 62 between the valve 65 and the chamber 13. The tank 67 is of sufficiently large size to cause pressurization of the second hopper S when the valve 31 is opened without material loss of pressure in the charging chamber 13 and injector tube 15. If desired, a second pipe 68, equipped with a check valve 69 is connected to the supply pipe 62 intermediate the supply valve 65 and the chamber 13 for admission of suitable inert gas, such as nitrogen, to the system, whereby to minimize oxidation of the bulk solids during the feeding thereof to the cupola. Further, if desired, another air supply pipe 70 is connected to the pipe 62 between the supply valve 65 and the chamber 13, the pipe 70 being provided with a valve 71 and being connected to the above mentioned source of high pressure air, not shown. It will be no-ted that the connection of the pipe 662 to the housing section 11 directs air toward the outlet 55 and, when the valve 71 is opened, high pressure air blowing through the pipe 62 aids in moving any of the bulk solids which might tend to adhere to the outlet end portion of the chamber 13 and injector tube 1S.

We provide novel control means whereby the above described apparatus may be manually controlled as to some of its functions, or automatically operated in automatically repeated cycles, now to be described. The control means, see FIG. 4, comprises a main switch 72, a manually operated gang switch 73 by means of which the system is rendered automatic or manually controlled, a pair of relays 74 and 75 having normally open switches 76 and 77 respectively, a plurality of time delays 7S, 79, 89, 81, 82 and 83, a normally open limit switch S4 and a pair of manually operated momentary contact switches $5 and 86. The limit switch 84 is preferably mounted on the cylinder 33 and is adapted to be closed by the piston plunger 32 during closing movement of the valve ele'- ment 31. The time delay relays 78-83 are of commercially available types including switches that are adapted to be opened or closed at desired intervals following energization of the relays. The relay 78 includes a normally open switch 87, the relay 79 including a pair of normally closed switches S3 and S9, the relay 89 including a normally closed switch 90 and a normally open switch 91, the relay 81 including a normally closed switch 92 and a ynormally open switch 93, the relay 82 including a pair of normally closed switches 94 and 95, and the relay 83 including a normally closed switch 96. The relay circuit includes a pair of power leads 97 and 98 which may be assumed to be connected to a source of electrical potential, not shown.

The gang switch 73 comprises a plurality of switches 99, 11M), 191 and 102 and, when the switch 73 is positioned for automatic operation of the apparatus, the switches 99 and 101 are open and the switches 109 and 162 are closed, as shown. When the gang switch is positioned as shown in FIG. 4, and the main switch 72 closed, relays 74, 78 and 79 are immediately energized, these relays being disposed in a circuit including the normally closed switch 95 and switch 102. Energization of control relay 74 causes immediate closing of its switch 76 to energize the motor 23 and resultant feeding of bulk solids to the first receiving hopper 7. After a predetermined time interval, the switches 88 and 89 open, de-energizing relay '79 and control relay 74 to cause opening of the switch 76 and deenergization of the feeding motor 23. Delayed closing of the switch S7 closes a circuit including time delay relay 89, solenoid 37, and switches 95 and 192, to impart movement of the valve spool 36 in a direction to cause the valve element 26 to open and the valve element 31 to Ibe closed, whereby the bulk solids delivered to the first hopper 7 ilow into the second hopper 8. As the valve element 31 closes, the piston plunger rod 32 closes the limit switch S4. Then, when switch 91 is closed, the solenoid 59 and time delay relay S1 are disposed in a closed circuit including switches 92, 84, 91 and 19t). Closing of the limit switch S4 and relay switch 91 causes energization of the solenoid 59 to open the valve 57 whereby high pressure air is introduced to the charging chamber 13 to inject a previously deposited charge of solids to the cupola. The solenoid 59 is deenergized by delayed opening of switch 92.

After a predetermined time interval, switch 90 opens to deenergize solenoid 37 to permit the valve spool 36 to return to its position of FIG. 3 to cause quick closing of the valve 26 and relatively slow opening of the valve 31 to permit the solids in the second receiving hopper 8 to flow into the charging chamber 13. During this time, deenergization of the time delay relay '79 due to opening of the switch 88 has caused the switch 89 to be reclosed to again energize control relay 74, Vclosing switch 76 and energizing the feeding motor 23 so that at subsequent charge of bulk solids is fed to the first hopper 7. It will be appreciated that, when the valve 31 opens, the limit switch 84 also opens, de-energizing relay 31. It should be noted that, closing of relay switches 91 and 93 causes energization of relays 82, 75 and 63. Energization of relay 75 causes its switch 77 to be immediately closed t-o establish a holding circuit for relays 32, 75 and 83 after relay 81 has been deenergized and switch 93 opened. This holding circuit is established through relay switch 91 and switch 14N). It will be noted that, during the time that relay switch 93 is closed, solenoid 66 is energized to open valve 65 whereby air is introduced to the chamber 13 and surge tanlr 67 to replenish any that may have been lost during opening of the valve 31 or to the cupola. The solenoid 66 is de-energized to close the valve 65 upon delayed opening of the relay switch 96.

Termination of the operating cycle and initiation of a new cycle is effected by delayed opening of the switch 95, breaking the circuit through relays 78, 79 and 74. Then, as soon as switch 94 opens, relay 82 becomes deenergized, causing re-closing of the switch 95 to again establish a circuit for relays 78, 79 and 74, and the operating cycle is repeated as above described.

When it is desired to exercise manual control over the system, the gang switch 73 is manipulated to close switches 99 and 161 and to open switches 169 and 192. With the gang switch 73 thus positioned, closing of the manually operated momentary contact switch 85 causes a circuit to be established including the closed switch 161, switch 95, relay 7S and relays 79 and '74 through the relay switches 83 and S9 respectively. 1t will be noted that a signal lamp 193 is arranged in parallel with the relay 74 in thecircuit containing the switch 39 and will be energized with the relay 74. Relay switch 76 closes immediately, energizing the feeding motor 23. At this time, the valve 26 is closed and valve 31 open, the bulk solids in the hopper 8 being discharged into the charging chamber 13. It will be further noted that, with the valve 31 in an open condition, the limit switch 84 is also open. As the switch S5 is held closed, relay switches 88 and 89 open to de-energize relay 74 to cause de-energization of the feeding motor 23, at which time the lamp 103 is extinguished. Opening of switch S8 causes the relay '79 to become deenergized; and closing of switch 87 causes relay Stb and solenoid 37 to be enen gized t-o open the valve 26 and close the valve 31, energization of solenoid 37 causing the limitswitch 84 to be closed. The timing of the relays '78, 79 and S0 is suchthat, when the lamp 103 is extinguished, the chamber 13 is charged and the valve 31 is closed, extinguishing of the lamp 103 indicating to the operator that the switch S may be released. It will be noted thatopening of the valve 31 permits the charge lfed into thehopper 7 by the feeding rotor 22 to drop into the second feeding hopper 8.

Manual closing of the momentary contact switch 86, with the limit switch 84 closed, completes a circuit including switches 99, 86, 84`and92, and the relay Si and solenoid 59, energization of solenoid 59 causing the valve 57V to be opened to introduce high pressure air into the chamber to propel the charge therein into the molten metal in the cupola 1. The propelling operation is very rapid and requires that the switch 86 be only momentarily closed. Should the operator hold the .switch `86 closed beyond the time necessary'for the charge to bel propelled, the relay switch 92 will open to tie-energize the solenoid 59, thus closing valve S7. The Vabove-described arrangement including the manual switches 85 and 86 permits of any desired time interval between loading, injection, and reloading of the apparatus.

While we have shown but a single loading and injecting apparatus in connection with a cupola, it will be appreciated that any desired number thereof may be used with a given cupola, preferably being circum-ferentially spaced thereabout. It will be further appreciated that each of a plurality of -such loading `and injecting mechanisms may be provided with individual electrical control systems or, if desired, a single control system as shown in FIG. 4 may be utilized t-o control all of the mechanisms simultaneously or in a given sequence.

While we' have shown and described our apparatus in connection with a foundry cupola, it will be further appreciated that the same may be used to inject additives of various types to material in a given container, such as a mixing tank or the like. It will be further understood that, while we have shown and described a commercial embodiment `of our apparatus, the same is capable of modication, and that modiiication may be made withv out'departure from the spirit and scope of the invention,

as defined in the claims.

What we claim is:

' 1. Apparatus for injecting bulk material into a pressurized receptacle, said apparatus comprising,

j (a) conduit means including an upper hopper for reception of bulk material from a source thereof andv a lower hopper for reception of said material from said upper hopper,

(b) a rst valve controlling flow of material from said upper hopper to said lower hopper,

(c) means defining a charge-receiving chamber having. a gas inlet at one end, .a material outlet at its opposite end, and a material inlet intermediate its ends for communication with said second hopper,

(d) a second valve for controlling iiow of said material' from said second hopper to said chamber,

(e) at least a portion of said chamber tapering from a vrelatively large cross-sectional area toward a relatively small cross-sectional area at the material outlet end thereof,

(f) an injector tube communicating with said material outlet for directing material from said chamber toA said receptacle.

(g) a normally closed check valve in said Achamber inl termediate said material inlet and said outlet,v (h) valve operating means for opening and closing said iirst and second valves in a predetermined sequence, whereby, when each thereof is opened, the other thereof is closed, (i) means including a gas valve for introducing material propelling gas at relatively high pressure to said gas i iniet,

8 (j) means for opening said gas valve to admit gas to said` chamber to open saidl check valve and propel a charge of material from saidchamber through said injector tube,

(k) and .independent means for admitting gas to said chamber atrelatively low pressure at least equal to the pressure in said receptacle, whereby to maintain said low pressure in said chamber and injector tube when said second valve'is open.

2. The structure defined in claim 1 in which said lastrnentioned means includes a pressure tank communicating with said chamber for maintaining said predetermined relatively low pressure in said chamber when said gas valve is closed and when said second valve'is opened, whereby to prevent material from saidvreceptacle from entering said injector'tube.

3. The structure defined in claimlin furtherfcombination with an independentk conduit communicating at one end with'the gas inlet portion of said chamber andat its opposite-end with the chamber adjacent said outlet; for aerating said material as the same enters said outlet responsive to introduction of gas under relatively highl pres-V sure to said chamber from said gas inlet, whereby to prevent undue compaction Yof said material as the same is propelled through said injector tube.

- 4. The structure'detined in claim 1 in which said valve operating means comprises a pair of valve operating devicestonc'for each of said Virstand second valves, and control mechanism including a control elementtmovable between a pair of operative positions, said valve operating devices being responsive -to movement of said'control element toone of said positions to open said first valve slowly and to rapidly close said second valve, said devicesbeing responsive `to movement of said control element'toward its other operative position to rapidly close said iirst valve and slowly open vsaid second valve, and means for imparting said movements to said control element.

5. The structure defined in claim 1 in which said valve operating .means comprises .a duid pressure circuit including a pairof piston plunger-equipped iiuid pressure cylinders one for each of `sadi first and second valves, a valve and a pair of metering devicesfor controlling yiiow of duid to said cylinders, said valve having a valve element movable between a pair of operative positions, said circuit being so arranged that movement of said valve element to one of said positions thereof causes fluid under pressure t0 berdirected to one of said cylindersto open said iirst valve and to the other of said cylinders to close said second valve, movement of said valve element to its other of said positions causing iiuid to bel directed to said other of the cylinders to open said second valveV and to said one of the cylinders to close said iirst valve, said metering devices being constructed and arranged to cause said first and second valves to be opened slowly and to be closed rapidly, and means for imparting said movements to said control valve element. i

6. The structure dened in claim 1 in which said chamber deiining means comprises primary and secondary housing sections, said'secondary housing section detining said tapering chamber portion, said' checkV valve being mounted in said tapering chamber portion and arranged in its closed position to admit lgas under said relatively low pressure to said primary chamberrportion when said high pressure gas valve is closed.

7. Apparatus for injecting bulk material into a pressurized receptacle, said apparatus comprising:

(a) conduit means including .an upper hopper for reception of bulk material from a Vsource Lthereof and a lower hopper for reception of said material from said upper hopper, n (b) a first valve controlling flow of material from said upper hopper to said lower hopper, (c) means defining a charge-receiving chamber having a gas inlet at one end, a material outlet at its opposite end for Vcommunication withY said receptacle, and a material inlet intermediate its ends for communication with said second hopper,

(d) a second valve for controlling ow of said material from said second hopper to said chamber,

(e) valve operating means for opening and closing said irst and second valves in a predetermined sequence and at diiferent speeds in the opening and closing directions, whereby, when each thereof is opened, the other thereof is closed,

(f) means includinga gas valve for introducing material propelling gas at relatively high pressure to said chamber through said gas inlet,

(g) means for opening said gas valve to admit gas to said chamber to propel a charge of material from said chamber through said material outlet.

, (h) and independent means for admitting gas to said chamber at relatively low pressure at least equal to the pressure in said receptacle, whereby to maintain said low pressure in said chamber and outlet when said second valve is open.

3. The structure defined in claim 7 in which said valve operating means includes a fluid cylinder adapted to be connected to a source of fluid under pressure, and a cooperating piston, one of said cylinder and piston being op- 5 eratively connected to one of said valves; and in further combination with control means operatively associated with said cylinder.

References Cited by the Examiner 10 UNITED STATES PATENTS 1,970,021 8/34 Peters 302-55 2,784,037 3/57 ReXroth 302--36 3,086,823 4/ 63 Rexroth 302--36 15 FOREIGN PATENTS 1,094,662 12/ 60 Germany.

SAMUEL F. COLEMAN, Primary Examiner.

20 ERNEST A. FALLER, Examiner. 

1. APPARATUS FOR INJECTING BULK MATERIAL INTO A PRESSURIZED RECEPTACLE, SAID APPARATUS COMPRISING. (A) CONDUIT MEANS INCLUDING AN UPPER HOPPER FOR RECEPTION OF BULK MATERIAL FROM A SOURCE THEREOF AND A LOWER HOPPER FOR RECEPTION OF SAID MATERIAL FROM SAID UPPER HOPPER, (B) A FIRST VALVE CONTROLLING FLOW OF MATERIAL FORM SAID UPPER HOPPER TO SAID LOWER HOPPER, (C) MEANS DEFINING A CHARGE-RECEIVING CHAMBER HAVING A GAS INLET AT ONE END, A MATERIAL OUTLET AT ITS OPPOSITE END, AND A MATERIAL INLET INTERMEDIATE ITS ENDS FOR COMMUNICATIN WITH SAID SECOND HOPPER, (D) A SECOND HOPPER TO SAID CHAMBER. FROM SAID SECOND HOPPER TO SAID CHAMBER. (E) AT LEAST A PORTION OF SAID CHAMBER TAPERING FORM A RELATIVELY LARGE CROSS-SECTIONAL AREA TOWARD A RELATIVELY SMALL CORSS-SECTIONAL AREA AT THE MATERIAL OUTLET END THEREOF, (F) AN INJECTOR TUBE COMMUNICATING WITH SAID MATERIAL OUTLET FOR DIRECTING MATERIAL FROAM SAID CHAMBER TO SAID RECEPTACLE (G) A NORMALLY CLOSED CHECK VALVE SAID MATERIAL TERMEDIATE SAID MATERIAL INLET AND SET OUTLET, (H) VALVE OPERATING MEANS FOR OPENING AND CLOSING SAID FIRST AND SECOND VALVES IN A PREDETERMINED SEQUENCE, WHEREBY, WHEN EACH THEREOF IS OPENED, THE OTHER THEREOF IS CLOSED, (I) MEANS INCLUDING A GAS VALVE FOR INTRODUCING MATERIAL PROPELLING GAS AT RELATIVELY HIGH PRESSURE TO SAID GAS INLET, (J) MEANS FOR OPENING SAID GAS VALVE TO ADMIT GAS TO SAID CHAMBER TO OPEN CHECK VALVE AND PROPEL A CHARGE OF MATERIAL FROM SAID CHAMBER THROUGH SAID INJECTOR TUBE, (K) AND INDEPENDENT MEANS FOR ADMITTING GAS TO SAID CHAMBER AT RELATIVELY LOW PRESSURE AT LEAST EAUAL TO THE PRESSURE IN SAID RECEPTACLE, WHEREBY TO MAINTAIN SAID LOW PRESSURE IN SAID CHAMBER AND INECTOR TUBE WHEN SAID SECOND VALVE IS OPEN. 